When formatting number to 2 decimal places you have two options TRUNCATE and ROUND. You are looking for TRUNCATE function.
Examples:
Without rounding:
TRUNCATE(0.166, 2)
-- will be evaluated to 0.16
TRUNCATE(0.164, 2)
-- will be evaluated to 0.16
docs: http://www.w3resource.com/mysql/mathematical-functions/mysql-truncate-function.php
With rounding:
ROUND(0.166, 2)
-- will be evaluated to 0.17
ROUND(0.164, 2)
-- will be evaluated to 0.16
docs: http://www.w3resource.com/mysql/mathematical-functions/mysql-round-function.php